I had crossed a marshy tract full of willows, bulrushes, and odd, outlandish, swampy trees; and I had now come out upon the skirts of an open piece of undulating, sandy country, about a mile long, dotted with a few pines and a great number of contorted trees, not unlike the oak in growth, but pale in the foliage, like willows.
There are no more uses of "undulate" in the book.
Show samples from other sources
A sidewinding snake uses less energy to cover the same distance as a laterally undulating snake uses.
The dancers’ arms undulated in unison to add to the ethereal effect.